1. Field of the Invention
The present inventon relates to a sail shortening roller for winding up a sail of a sailing boat on a tubular sheath mounted for rotation about a rigging cable, for example about the jib stay.
2. Description of the Prior Art
Generally, it is known that numerous devices of this kind have already been proposed, usually called jib or main sail roller reefers.
However, it has proved in use that these reefers do not allow all the expected results to be obtained, more especially for the following reasons:
They usually require for fitting a modification of the cable, generally a cut and a connection, because of the presence of the usual terminations of the cable such as crimped eyes, toggles or turnbuckles.
They are subject to defects in reefing the sail, this latter tending to form, during winding, folds or pockets due to slight axial displacements towards the middle of the sail along the tubular sheath during winding thereof or, quite simply, because of the shape of the sail (belly of the sail).
They comprise elements secured to the tubular sleeve or to the surroundings thereof which cause in the long run damage to the sail and which, when they are fitted by screwing or by riveting, considerably weaken the tubular element.
They do not allow good regularity of the rotational movement of the tubular element to be obtained particularly when reefing up of the sail takes place when the stay assumes camber under the effect of the wind or because of excessive play between the stay and said tubular element.
They often cause locking of the rotation of the tubular element about the cable following winding up of the halyard used for hoisting the sail or the handling rope which operates the reefer. The invention relates more particularly to a sail shortening device having high reliability and whose structure is especially designed so as to avoid the above-mentioned disadvantages and so as to further obtain numerous advantages which will be mentioned in the following description.